Lucky has a bag of gold coins. She hides $21$ gold coins in the backyard and $14$ gold coins in the kitchen. Lucky still has $13$ coins to hide. How many gold coins were in Lucky's bag at the start?
Solution: Lucky hid ${21}$ coins in the backyard and ${14}$ coins in the kitchen. $?$ $21$ $14$ Backyard & Kitchen coins Backyard coins Kitchen coins ${21} + {14} = {35}$ Lucky still has ${13}$ coins to hide. $?$ $35$ $13$ Total coins Backyard & Kitchen coins Coins left ${35} + {13} = 48}$ There were $48}$ total coins in her bag. Lucky had $48}$ gold coins in her bag at the start.